The European Club Association (ECA) says introducing promotion and relegation to the Champions League could be "logical" as it begins talks with UEFA over the structure of its competitions.
The ECA, which represents over 200 clubs across Europe, started talks with UEFA last week over making changes to competitions, including the Champions League from 2024 onwards.
The chairman of the ECA, Andrea Agnelli, says promotion and relegation is "natural" in domestic leagues and "might be logical internationally".
Agnelli, who is also the chairman of Juventus, added talks between the ECA and UEFA could take up to 18 months.
Qualification for the Champions League is currently determined by where teams finish in their domestic league. The winner of the previous season's Europa League is also guaranteed entry to the group stages.
The ECA has also suggested European leagues could begin to coordinate their fixtures to avoid competing with each other for viewers.